The actions of Henry Dundas, the 1st Viscount Melville, whose statue dominates St Andrew Square in the city’s New Town, in proposing the gradual ending of slavery, at a time when immediate abolition was being proposed, are said to have resulted in an additional 630,000 slaves being transported from Africa to the Caribbean.
However, campaigners for the removal his statue or the rewording of the plague on the memorial are accused of “sensationalism” and spreading “misinformation” on Dundas by his direct descendants in the BBC Scotland documentary.
They insist that Dundas, who was home secretary at the time, was an “abolitionist” who proposed the gradual abolition of slavery as a way of ensuring that legislation would be passed.
The documentary reveals the sharp divide between historians over his role and motives.
It recalls the long-standing efforts by Sir Geoff Palmer, Scotland’s first black professor, to get the wording on the plaque on the Melville Monument in St Andrew Square altered to reflect his involvement in slavery.
The local authority agreed new wording in the wake of the Black Lives Matter protests around the world.
He tells Tuesday’s documentary: “About 630,000 slaves who were taken into slavery would not have been taken into slavery if Dundas had not set slavery out to be gradually abolished.”
Althea Dundas-Baker, the current owner of Arniston House, Dundas’s birthplace in Midlothian, said the targeting of his memorial, which was the focal point for Black Lives Matter demonstrations and vandalised in the summer, had done a “disservice” to the movement.
She said: “It is simply untrue that my ancestor prolonged the slavery. He had very little to do with it. The people that seem to be so determined to put out this message are in the wrong.
"We take it personally. It boils down to him being falsely accused of something. He is not here to defend himself. As ancestors and family members, it is our duty.”
Her daughter, Henrietta, adds: “It is factually incorrect that Henry was responsible. Effectively he has has been made out to be a mass murderer when, in fact, he was in favour of abolishing slavery. He was an abolitionist.
"His intention was to end slavery, but there had to be a political process. He's been falsely accused of something that is not correct.”
The documentary features an interview with Marianna Spring, a BBC specialist on the spreading of misinformation, or “fake news”, on social media.
She says: "When it comes to those arguing that he [Henry Dundas] was not an abolitionist and that the plaque needed to be put up on the statue, we noticed that the conversation tends to be historians or other pro Black Lives Matter protesters and campaigners. That all appears to be authentic.
"On the other side of the debate, with those who argue that Henry Dundas was an abolitionist, we see examples of inauthentic accounts. They exclusively talk about the particular debate about this statue.”